Greek National Road 77 is a national highway on the island of Euboea, Greece. It connects Chalcis with Aidipsos via Agia Anna and Istiaia.
Ministerial Decision G25871 of 9 July 1963 created the EO77 from the old EO12, which existed by royal decree from 1955 until 1963, and followed the same route as the current EO77.